MD5 File Validation

The MD5 File Validation feature provides a Cisco IOS software command you can use to ensure file validation using the Message Digest 5 (MD5) algorithm in the Cisco IOS File System (IFS).

The MD5 File Validation feature allows you to check the integrity of a Cisco IOS software image by comparing its MD5 checksum value against a known MD5 checksum value for the image. MD5 values are now made available on Cisco.com for all Cisco IOS software images for comparison against local system image values.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see
Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to
www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Restrictions for MD5 File Validation

The MD5 File Validation feature can only be used to check the integrity of a Cisco IOS software image that is stored on a Cisco IOS device. It cannot be used to check the integrity of an image on a remote file system or an image running in memory.

Information About MD5 File Validation

MD5 File Validation Overview

The MD5 File Validation feature provides a mechanism for users to verify that system image files are not corrupted or incomplete. This feature uses the industry-standard MD5 algorithm for improved reliability and security. MD5 file validation computes and displays the MD5 values from the Cisco IOS command-line interface (CLI). Files do not have to be checked on another device.

Note

The MD5 file does not have to be on the router in order to verify the Cisco IOS software image.

How to Validate Files Using the MD5 Algorithm

Verifying an Image

The MD5 File Validation feature allows you to generate the MD5 checksum for the Cisco IOS image stored on your router and compare it to the value posted on Cisco.com to verify that the image on your router is not corrupted.

Perform this task to run the MD5 integrity check after transferring an image file.

Image Information

You can obtain the MD5 value for your system image from the Software Center at Cisco.com. The most convenient way to get this value is to click the name of the file prior to download. For example, if you select the 12.2.2T4 Release for the 3640 Platform with the Enterprise Plus Feature Set, before clicking the Download button, you can click the filename for the image (c3640-js-mz.122-2.T4.bin) and the image information will be displayed.

Image information typically includes the Release, Description, File Size, BSD Checksum, Router Checksum, Date Published, and MD5 value for the image. You should record the MD5 value for the image prior to download. However, if you do not have the MD5 value for a previously downloaded image, you can select the same image on Cisco.com (using the same process you would use to download the image) to get the MD5 value.

Troubleshooting Tips

Configuration Examples for MD5 File Validation

Verifying an Image Example

In the following example, the /md5 keyword is used to display the MD5 value for the image stored in disk1 of the device. The MD5 value shown in the last line can be compared to the value provided on Cisco.com.

RFCs

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

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Feature Information for MD5 File Validation

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to
www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Table 1 Feature Information for MD5 File Vaildation

Feature Name

Releases

Feature Information

MD5 File Validation

12.2(4)T 12.0(22)S

The MD5 File Validation feature allows you to check the integrity of a Cisco IOS software image by comparing its MD5 checksum value against a known MD5 checksum value for the image.